Phone keypad problem?General

Anyone have a problem with the onscreen keypad not coming up when a call is in progress? My credit card company called me with an automated message to notify me about possible fraud on one of my credit cards. At one point to continue with the call, I had to press "1", but the onscreen keypad would not come up when I tapped on the keypad icon. I kept tapping but nothing happened, and ended up losing the call. The keypad icon has worked on other calls, just not this one.